Hair treatment applicator



FIG. 1 is a perspective view of a hair treatment applicator, embodying our new design;

FIG. 2 is a side view thereof;

FIG. 3 is a top view thereof; and,

FIG. 4 is a front view thereof.

The broken lines shown in the drawing disclosure are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a hair treatment applicator, as shown and described. 